Plasma cells and plasmacytoid features in thyroid lesions

Area of Science:

• Endocrinology
• Pathology
• Cytopathology

Background:

• Thyroid lesions are typically of epithelial origin with papillary or follicular patterns.
• Rarely, thyroid lesions involve plasma cells or plasmacytoid cells, mimicking other conditions.
• These include benign conditions like chronic lymphocytic thyroiditis and neoplasms such as plasmacytoma.

Purpose of the Study:

• To review thyroid entities exhibiting plasmacytoid cell features.
• To highlight diagnostic challenges due to rarity and overlapping cytomorphology.
• To discuss the relevance of these findings to the Bethesda System and WHO classification.

Main Methods:

• Literature review of thyroid lesions with plasmacytoid cytomorphology.
• Analysis of diagnostic criteria and challenges.
• Correlation with established classification systems.

Main Results:

• Thyroid lesions with plasmacytoid features can be benign (e.g., chronic lymphocytic thyroiditis) or malignant (e.g., medullary thyroid carcinoma).
• Distinguishing true plasma cells from plasmacytoid features is critical for diagnosis.
• Diagnostic difficulties arise from rarity, overlapping features, and selection of ancillary studies.

Conclusions:

• Thyroid lesions with plasmacytoid features require careful diagnostic consideration.
• Understanding these rare entities is crucial for accurate classification within the Bethesda System and WHO guidelines.
• Appropriate use of ancillary studies aids in differentiating these challenging thyroid lesions.